A display device employing a touch panel as an input device comprises: a display panel for displaying an image, and the touch panel which is placed over the display panel. An electrostatic capacitive method, in which contact of a finger or the like with an operating surface of the touch panel is detected as a change in electrostatic capacity, is widely used as a method for detecting a contact position of a finger or the like on the touch panel. In a touch panel employing an electrostatic capacitive method, a conductive film of the touch panel comprises: a plurality of first electrodes extending along a first direction, a plurality of second electrodes extending along a second direction orthogonal to the first direction, and a transparent dielectric layer interposed between the first electrodes and the second electrodes. The contact position of a finger or the like on the operating surface is then detected on the basis of a change in electrostatic capacity between one first electrode and each of the plurality of second electrodes being detected for each first electrode.
According to an example of this kind of conductive film, the respective first electrodes and second electrodes are formed by a plurality of fine electrode wires comprising a metal such as silver or copper (e.g., see Patent Document 1). By using a metal as the material of the electrode wires, it is possible to achieve rapid responsiveness and high resolution when the contact position is detected, while it is also possible to reduce the size of the touch panel and to reduce production costs.
In a configuration in which the electrode wires are formed from a metal which absorbs or reflects visible light, a plurality of first electrodes and a plurality of second electrodes form an electrode wire pattern in which the electrode wires forming said electrodes are alternately intersecting, as seen from the operating surface of the touch panel. Meanwhile, a black matrix defining a plurality of pixels along a first direction and a second direction also forms a pixel pattern which is a lattice-shaped pattern in a display panel on which the touch panel is laminated.
Here, a periodic structure of the electrode wire pattern and a periodic structure of the pixel pattern lie one over the other as seen from the operating surface of the touch panel, and an offset in the two periodic structures sometimes induces moiré. When this moiré is observed, there is a reduction in the quality of an image observed on a display device. The shape and period of the electrode wire pattern is therefore set to a shape and period such that moiré is unlikely to be observed when the electrode wire pattern and the pixel pattern are placed one over the other.